McLachlan and Wilson’s research led then to develop a revolutionary new theory of how the auditory system works. This new theory proposes that animals first recognize the sound sources before processing other features such as the sound’s pitch or location.
"This makes sense from an evolutionary point of view because the most important thing an animal needs to know is whether they can hear predators or preys," McLachlan explained. "It also makes sense from an information processing point of view because we can use prior experience to adapt our hearing to new circumstances."
Since sound recognition involves developing long-term memories for sounds, this theory helps to explain why different individuals can have such different reactions to sound, especially music.
Prototypes of the new harmonic gongs.
To test this even further, McLachlan conducted a controlled study involving the Indonesian gamelan, a percussion instrument known to sound dissonant to the Western ear.
In the gamelan study, one group of Western musicians who had learnt to play gamelan instruments were asked to find the pitch in those instruments. Another group of Western musicians who had never encountered the gamelan were asked to do the same.
The results revealed that people who played the gamelan could find the pitch of the gamelan instruments very accurately and found it to be quite harmonious, whereas, the Western musicians who were untrained in the gamelan could not.
The study demonstrated that the perception of pitch, harmony, scale and rhythm are learnt within particular musical cultures, which suggests that musical structures are not physically or biologically determined.
“We can recognize sounds because that’s what we have to do in the real world, but to accurately pitch sound requires training,” McLachlan said.
This refined pitch processing is very involved, but according to McLaclan and Wilson, we all have the ability to build up these memories for sound -- neuroscientists refer to this ability as 'brain plasticity.'
The study is a revelation for many people who have long held the belief that there are some people who are simply born with the ability for music.
McLachlan hopes that this new-found insight into our auditory system, along with his new instruments, will increase music participation and make playing music something ordinary people do as regular as exercise.